1. Field
Aspects of the present invention relate to a high voltage power supply (HVPS) employed in an image forming apparatus, which has a small size, and improved efficiency and performance by using an optimal layout.
2. Related Art
FIG. 1 is a block diagram of an arrangement of components on a substrate in a typical high voltage power supply (HVPS) circuit utilized in an image forming apparatus, such as a laser printer, a facsimile machine, a photocopier, and a multifunctional product. As shown in FIG. 1, the high voltage power supply (HVPS) comprises an input connector 110; first and second high voltage output controllers 120 and 130; first through eighth transformers 140, 142, 144, 146, 150, 152, 154, and 156; and output terminals 141, 143, 145, 147, 151, 153, 155, and 157, disposed on a substrate (circuit board) 100. The first high voltage output controller 120 generates a high voltage, and is disposed in a first section of the substrate 100 closely adjacent to output terminals in secondary sides 151, 153, 155, and 157 of fifth through eighth transformers 150, 152, 154, and 156. However, because of an inappropriate disposition of the output terminals, not enough separation between output terminals is provided for the output terminals of the fifth through eighth transformers 150, 152, 154, and 156 disposed on a second section of the substrate 100. In addition, an electromagnetic effect occurs between each component, since signal lines provided from an input connector 110 are disposed in a complicated manner on and beneath the surface of the substrate 100. The larger size of the substrate 100 results in a larger image forming apparatus.
The above-described layout causes an overshoot due to the separation between the output terminals 140, 142, 144, 146, 150, 152, 154, and 156, damage to the image forming apparatus caused by an electric arc, and instability of a high voltage output from the HVPS caused by the electric arc. The size of the substrate 100 thus becomes larger and an inefficient jumper occurs. Given the micro-miniaturization trend of recent years, the large size of the substrate 100 creates a significant limitation. In particular, the separation between the components on the first section of the substrate 100 and the components on the second section of the substrate 100 second, as well as the separation between the high voltage output terminals, must be carefully calculated, since the HVPS circuit may control voltages ranging from a low voltage at 24.5 V to a high voltage, according to a predetermined number of turns. Unlike the output terminals 141, 143, 145, and 147 disposed on the first section of the substrate 100, the output terminals 151, 153, 155, and 157 disposed on the second section of the substrate 100 generate a voltage higher than 5 kV. If the separation distance is not enough and a pattern between the first high voltage output controller 120 and the second high voltage output controller 130 is arranged in a complicated manner, an abnormal operation may occur when generating an output voltage, which may cause the image forming apparatus to overheat or malfunction.